This invention is directed to a nuclear fuel system and in particular to nuclear fuel rods incorporating a protective intermediate layer between the fuel and its zirconium alloy sheath (cladding), and a method for applying the layer in a nuclear fuel element.
In the operation of nuclear reactors employing sintered fuel tablets (pellets) sheathed in zirconium alloy sheaths, it has been found that, during irradiation, cadmium is released from the fuel and migrates outwardly to the inner surface of the sheath where it can create an embrittlement phenomenon, resulting in sheath failure due to stress corrosion cracking.